Importance of Patterning Tools in Electronic Module Production
In the manufacturing of many electronic modules such as printed circuit boards (PCB's) and multi-chip modules (MCM's), the production equipment represents a major cost element, accounting for approximately two-thirds of the total facility cost. Of the many process steps involved in electronic module fabrication, the most critical are those required for patterning the dielectric and metal layers. The capabilities and cost-effectiveness of the patterning (i.e., lithography) technology impact the performance and cost of the module, and ultimately determine the size and cost at the electronic system level. This makes patterning tools the largest and most critical component of the total production equipment investment. Typical costs of individual tools range between $1.5 and 4 million. A high-volume production facility would have multiple lithography tools. In addition, operating expenses add several hundred thousand dollars per year to the net cost of running such tools. Thus, significant progress will be made toward wider commercial applicability of low-cost electronic modules by development and implementation of new high-throughput, cost-effective patterning equipment.
Roll-to-roll processing is considered an attractive manufacturing technology for further reducing the module cost through naturally simpler automation and reduced overhead. By allowing the material to be processed in continuous rolls, there are fewer opportunities to contaminate or damage the material through handling. Roll-to-roll processing is also an inherently easier process to automate. This cuts down on labor costs and increases the throughput. Finally, roll-to-roll processing introduces very small overhead time to the process cycle. When handling discrete parts in a conventional process, one part must be removed before the next part can be loaded. This is not the case for fabricating electronic module panels with continuous rolls, in which removal of a processed panel from the active region of the equipment can proceed simultaneously with loading of the next panel. The reduced overhead advantage is perhaps the most important in connection with high-speed exposure systems, because, the lower the overhead is, the greater will be the effectiveness of fast exposures in delivering a higher net throughput.
Existing patterning tools for exposing large substrate panels suffer from numerous shortcomings, as described below. Tools that can pattern large, roll-fed sheets with high yields and at a low cost per exposure do not exist. Thus, there is a great need for a roll-to-roll patterning system that can help produce electronic modules cost-effectively.